In some cases, src.sig_peak remains undefined as 0, which was definitely
the case when using the OSD, since it never got passed through the usual
color space normalization process. Most robust work-around is to simply
force the normalization at the site where it's needed. This ensures this
value is always valid and defined, to make the peak-dependent logic in
these two functions always work.
Fixes 4b25ec3a9d
Fixes #6917
Fixes #6918